Research And Implementation Of Dynamic Dust Detection Method Based On Geostationary Meteorological Satellite

With the development of remote sensing technology,more and more polar-orbiting satellites and geostationary meteorological satellites have been launched successfully,and put into the use of earth observation.This provides a necessary condition for the further study on the variation and distribution of dust aerosol and its influence on the climate system.In the study of quantitative retrieval of dust aerosol parameters by infrared remote sensing,dust identification is an important and difficult task.The misjudgment of dust coverage may lead to the failure of the final inversion results.Therefore,the correct result is the premise and foundation of the whole quantitative inversion.The dust particles in the air have a strong response signal in the infrared channel,which is manifested in the following two aspects.On the one hand,the emissivity of dust particles in the 12?m channel is higher than in the 11?m channel,resulting in a bright temperature difference between the two channels.On the other hand,due to the infrared signal emitted from the surface of the earth,it causes the decrease of the brightness temperature,which is called the infrared difference dust index.These can be used to track and identify the effective parameters of dust information.Currently,the identification of dust is mainly aimed at the 11?m and 12?m channels brightness temperature change information,which is based on fixed threshold.The method used the characteristic that the brightness temperature difference between 11?m and the 12?m channels is negative to distinguish the dust from other detection targets.However,it is easy to produce a bigger misjudgment.The main reason is that the brightness temperature of the 11?m and the 12?m channels varies significantly with time and space.Therefore,judging by the fixed threshold,the pixels will be misjudged because of the fluctuation of brightness temperature.To overcome this problem,it propose a dust detection method based on dynamic threshold of geostationary meteorological satellite.The clear-sky background field of 11?m brightness temperature and its difference with 12?m were established by making use of Himawari-8 the new generation of geostationary meteorological satellite.While combining with the bright temperature variation characteristics of 11?m and 12?m channel under the conditions of dust atmosphere the detection was performed.The experimental results show that the proposed method is more accurate than the fixedthreshold method and the results are more accurate and stable.It can be used to detect the dust in daytime and night.The research work of this paper includes the following three parts:1.In this paper,Himawari-8 data is used to construct the background field as a dynamic threshold.Based on the spectral characteristics of the brightness temperature difference between the 11?m channel and the 12?m channel,a dynamic dust detection method based on geostationary meteorological satellite is proposed.2.It is based on the construction of the infrared difference dust index in this paper,according to its change with time,we can observe the changes in the intensity of dust in different areas of the day.Therefore,by using the characteristics of the high phase of Himawari-8,the dynamic monitoring of the dust information can be realized.3.The method,which is proposed in this paper for dynamic dust detection,was applied in the dust information extraction in the northwest of China from March 1 to 20,2016.The experimental results show that this method not only can improve the accuracy of dust detection,but also can be applied to extract the dust information at night.Consequently,this method provides a reliable means for the study of the dust weather in China.